Photoelectron interference in metallocenes: a probe of geometrical and electronic structure

The present work concerns the study of high-energy structures in the photoionization of Mg and Be metallocenes due to photoelectron diffraction. The influence of geometrical structure is studied by varying the metal–ring distance in MgCp2, as well as that in the permethylated compounds MgCp2* and BeCp2*. The cross section ratios relative to the two outermost valence ionizations have been studied and found to be very sensitive to the value of the metal–ring distance and to be able to resolve ambiguities in present experimental values. Further differences are attributed to minor changes in the electronic structure. The results confirm that long-range oscillations in molecular photoemission cross sections constitute a general phenomenon and are an easily measurable observable that can be used to obtain important information on the geometric and electronic structure of the target.